蚯蚓纤溶酶增加胃癌细胞对放射线敏感性的实验研究

Study on enhancing radiosensitivity of fibrinolysin extracted from earthworm on gastric adenocarcinoma cell line

目的探讨蚯蚓纤溶酶对胃癌细胞株MGC803的放射增敏作用及机制。方法采用克隆形成实验观察蚯蚓纤溶酶的放射增敏作用;流式细胞术观察药物对胃癌细胞株MGC803周期分布的影响;RT-PCR法检测药物对细胞内硒谷胱甘肽过氧化物酶(SeGPx)基因表达的影响。结果蚯蚓纤溶酶对胃癌细胞有放射增敏效应,100uku/L、300uku/L蚯蚓纤溶酶的放射增敏比分别为1.06和1.14。射线照射后MGC803细胞发生G1期阻滞,蚯蚓纤溶酶对细胞G1期阻滞无明显影响;PCR检测发现射线可诱导的SeGPxmRNA表达下调,蚯蚓纤溶酶能够增强射线诱导的SeGPxmRNA表达下调作用。结论蚯蚓纤溶酶能够增加胃癌细胞对放射线的敏感性,增敏机理可能与药物下调细胞内抗氧化酶SeGPx基因表达有关。

Objective： To study the mechanism of radiosensitizing effect of fibfinolysin extracted from earthworm and its mechanism. Methods：Human gastric adenocarcinoma cell line MGC803 were treated with the fihrinolysin. Cell survival was determined by clonogenic assay. The cell cycle distribution was checked via flow cytometer after fihrinolysin treatment. RT-PCR was used to determine the gene expression of seleniun dependent glutathione peroxidase （SeGPx）. Results： Under the experimental condition, fibrinolysin extracted from earthworm definitely enhanced radiosensitivity of MGC803 cells. Cell survival expriment showed sensitivity-enchancementratio of 1.06 and 1.14 for 100uku/l and 300uku/l of the fihrinolysin respectively;DNA flow cytometric analysis indicated that the fihrinolysin was incapable of abrogating the G1 arrest induced by T-rays;however, the the expression of SeGPxmRNA decreased after the fibrinolysin and T-rays treatment. Condusion：Fibrinolysin extracting from earthworm might be a pential radiodsensitizer for gastric adenocarcinoma. In addition, our data show that downregulating of SeGPxmRNA expression may play a key role in the radiosensitizing effect of the fibrinolysin.